Radio apparatus



Dec. 11; 1928. 1,694,396

P. H. ROOTH RADIO APPARATUS Filed June 15, 1927 00 H L, JQX E Q Paul H R Patented Dec. 11, 1928.

UNITED STATES PAUL H. BOOTH, OF

CHICAGO, ILLINOIS.

RADIO APPARATUS.

Application filed June 15,

The present invention in general pertains to radio apparatus and more particularly to an inductance unit or vario-eouplcr.

The object of my invention is to provide an improved variable inductance unit adapted to be interposed in the tuner part of a radio receiving circuit, and having a greater range of selectivity than the conventional type of vario-coupler. That is to say, the device of my invention permits of a much fine-r tuning of the radio circuit connected thereto.

In accordance with the general features of my invention, there is provided a vario: coupler comprising a pair of concentric coils, and a rotary coil disposed within said concentric coils and capable of a move ment of approximately 180. The coils are disposed in inductive relationship. One of the concentric coils comprises a primary winding, and the other a secondary winding. The rotary coil includes a winding connected in series with said primary winding and which is adapted to be disposed between the primary winding and the antenna of the radio receiving set. The position of this rotary winding is such that it is adapted to vary the sensitivity of said primary winding.

Other objects and advantages of my invention will more fully appear from the following detailed description taken in connection with the accompanying drawing which illustrates an embodiment thereof and in which:

Figure 1. an elevation of the vario-coupler of my invention;

Figure 2 is a vertical cross-sectional view taken through the device shown in Figure 1;

Figure 3 is another view of my device looking at it from another angle, and

Figure 4 is a diagrammatic view illustrating the application of my novel vario-coupler to a radio circuit.

In the drawing: The reference character 10 designates generally my novel vario-coupler. This device i is adapted to be connected to a radio circuit,

such as a tour-tube regenerative circuit shown in Figure 4. As shown in Figure 4,

the device 10 includes a transformer comprisinga primary winding 11, a secondary windingglil, and a rotary winding 13 for varying the sensitivity of the winding 11. In addition to being disposed in inductive relationship, the three windings are disposed between the antenna 14 and the circuit 11'. Also the windings 11 and 12 may be connected to the ground 16 by a lead 17. Now it will be read- .tric with the other two sh 1927. Serial No. 198,880.

ily evident that the vario-coupler of my invention permits of a much finer tuning of the radio circuit 15 connected thereto, inasmuch as the variable inductance unit or coupler is interposed in the tuner part of the radio receiving circuit, and has a greater range of selectivity than the conventional type of vario-coupler. Because the primary winding 11 is positioned intermediate the rotary winding 13 and the secondary winding 12', and is stationary with respect to the latter winding, the electric and magnetic couplings of the windings 11 and 12 are substantially constant and ll'lOVQll'lQl'lt of the winding 13 will have no effect of practical in'iportance on the constants of the winding 12. I shall now proceed to describe in detail the structural details of the coupler 10.

The device 10 preferably comprises three sleeves 18, 19, and adapted to be disposed in concentric relationship. Sleeve 18 car rice the varying coil or winding 13; Sleeve 1.) has mounted thereon the primary winding 11, and sleeve 20 has disposed thereon the secondary winding These sleeves may be made of any suitable insulating material, such, for QXHIHPlQ, as a phenolized condensation product. The two sleeves 19 and 20 are at all times disposed in substantially concentric relationship and are suitably anchored together by means of bolts j and nuts 21. Also although the sleeve 18 is adapted to be disposed in a position concen- -es, still it will be evident that the sleeve is capable of a move ment of approximately 180 That is to say, the sleeve 18 may be moved from a concentric position with respect to the other sleeves to a position at right angles to said sleeves.

The winding 13 on sleeve 18 has one of its ends connected to a terminal 22 carried by sleeve 19 and has its other end connected to a terminal 23 also carried by sleeve 19. The terminal 22 may be connected by a suitable wire lead to the antenna 14 shown in F igure 4. 'Iheterminal is connected to one end of the winding on sleeve 19. The other end of this latter winding 11 is connected to a terminal 24 carried by the outer sleeve 20. If it so desired, the ground wire 17 may be connected to this terminal, as shown in F igure 2. The winding 12 on the outer sleeve 20 has one of its ends connected to the terminal 24 and has its other end connected to the terminal 25 also carried by sleeve 20. Both the terminals 2st and may be connected by suitable lead wires to the ends of the radio circuit 15 in a manner well known to those skilled in the radio art.

The rotary sleeve 18 is spaced from and mounted in the sleeve 19 by means of a mountingdesignated generally by the reference character 26. This mounting preferably comprises three parts including an angular member 28 secured to the sleeve 18, an angular member 29 secured to the sleeve 19, and a shaft member 30 extending through member 29 and fastened to member 28 for rotating the sleeve 18. The member 28 includes a hub portion 31 through which extends a part of sha ft 30. This part of the shaft is connected to the hub by means of a setscrew 232. The hub 31 is preferably disposed at an angle of approximately with respect to the plane at the associated edge of sleeve 18. The member 29 includes a mounting portion 32 having an opening 34. through which the shaft 30 extends. This portion 83 is dis posed substantially parallel to the hub portion 31 of. member 28, when the sleeve 18 is concentric with the other sleeves. Also the portion 33 has a threaded hole through which a screw may be threaded for mounting the member 29 upon a suitable support. Shaft 80 is preferably provided with a shoulder 36 adapted to abut the surface of portion 33 so as to prevent the hub 31 of member 28 from moving away from member 29.

By rotating shaft 30, it is possible to move the sleeve 18 from a position concentric with the other sleeves to a position at right angles to the sleeves, as shown in Figure 2. In practice, it desirable to permit the sleeve 18 to rotate only 'lhereftnc, in order to limit the rotary travel of thi :lceve, the hub 31 is provided with a projection or lug 1t) adapted to engage stops 4-1 formed integral with member 29. Obviously by rotating the sleeve 18 the coil or winding 13 thereon will operate to vary the inductance of the primary circuit. This in turn will vary the range of selec ivity of the two windings 11 and 13. thus permitting of a much tiner tuning of the radio circuit. connected thereto.

1 claim as my invention:

in a trio-coupler for radio circuits, a stationary prin'iary winding, a winding rotatable within said primary winding and connected at oneend to one end of said stationary primary vinding, and a stationary secondary winding enclosing the said stationary primary winding and spaced therefrom and shielded from said rotatable winding by said stationary primary winding.

In testimony whereof I have hereunto subscribed my name at Chicago, Cook County. Illinois.

PAUL H. BOOTH. 

